Investigation of the structure of compacts and sheets of an Al-Cu-Li alloy strengthened by Al2CuLi (T1) particles

Abstract

X-ray diffraction and electron microscopy have been used to investigate structural states of the material of compacts and sheets of an aluminum-copper-lithium alloy with a lithium content corresponding to the field of equilibrium of a solid solution with the phase T 1 (Al2CuLi). In pressed strips, there arises a multicomponent texture (Bs “110”〈112〉, Cu “211”〈111〉, S “123”〈hkl〉) typical of pressed articles of aluminum-lithium alloys. Their microstructure was characterized by the presence of slip bands oriented in the rolling direction. The formation of lamellar precipitates of the T 1 phase at slip-band boundaries in the process of deformation is supposedly stimulated by Shockley partial dislocations. In hot-rolled sheets, there arose an unusually intense nearly single-component texture of the Ex 1 “011”〈111〉 type, whose appearance is mainly caused by the cross rolling of the sheets. The reduced strength characteristics of the sheets examined are connected with a sharply oriented character of the structure of both the matrix phase and the strengthening T 1 phase. A quasicrystalline phase T 2 present in the material and the precipitates of the δ′ phase exert no marked effect on the level of mechanical properties.